Some wireless telephone users need to send or receive digital data. Such data may include computer data files, stock quotes, personal calendar data, business contact information, and innumerable other data subjects. Existing wireless telephone users are able to transmit such data, but with limitations on the transmission speed, economy, and location.
There are several different modes of wireless data transmission, with new alternative modes expected to be developed and implemented as technology progresses. Current modes include packet data transport modes such as SMS (Short Message Service), 1XRTT (Multi-Carrier 1X), GPRS (General Packet Radio Services), 3XRTT (Multi-Carrier 3X), and UMTS (Universal Mobile Telecommunication System), EDGE (Enhanced Data rates for GSM and TDMA Evolution), CDPD (Cellular Digital Packet Data) and BlueTooth. Various of these are adapted for use in conjunction with the various digital cellular voice transmission mode such as CDMA, GSM, and TDMA.
While of each of these is reasonably effective where implemented, no one mode is superior in all areas and instances. Even where a region is covered by one mode, there are localized areas where coverage is weak or unavailable. Thus, conventional digital cellular modems using any one mode are of limited use on some occasions when needed. The typical mode is for the user to employ a CDPD modem, which operates in only one mode.
To reduce the disadvantages of being tied to a single mode, one system employs the WAP (Wireless Access Protocol) communication standard and SMS. If a user fails to achieve digital data communication by the default mode of the handset, the user may manually select the alternate mode, and attempt to communicate in hopes that the second mode is effective. This is essentially a back up for when failure occurs, and is often an inconvenience to the user. Moreover, a marginal transmission may in fact occur with the first mode, but at relative high cost (either to the user or the carrier, such as when bandwidth is restricted), at relatively low speed, or with possible corruption of data. This marginal transmission may occur while the back-up mode was able to provide much better service, with that opportunity being lost because the user never was aware (in the absence of a complete failure of the primary mode) of the benefits of switching to the back up mode.
This system has the additional disadvantage in that it is incorporated into a hand set. Thus, as voice or data transmission technologies change, the entire handset may become obsolete, even when one aspect remains effective. In addition, a user opting to upgrade to data capability after owning a conventional handset must discard the handset.
One type of digital data transmission is locational data, such as provided by a GPS (Global Positioning System) receiver. Hand sets have included GPS capability, although these suffer from the disadvantage noted above in that one aspect of the unit may become obsolete before the other. In the case of expensive GPS circuitry, a user may occasionally wish to upgrade a telephone, except that the appreciable investment in a still-current GPS unit makes an upgrade unaffordable. GPS units have been used in conjunction with wireless handsets to collect and transmit GPS location data to a call center, which converts the data to a useful format such as a graphical GIF image, and transmits the image for viewing on the handset's display screen. While useful in some circumstances, this has limited use in transmitting the information to other remote units, or for actuation of location functions from anyone but the holder of the handset.
The present invention overcomes the limitations of the prior art by providing a method, device, and system for wireless communication of digital data that employs a mobile unit having a number of alternative transmission modes of digital wireless communication. The unit may be a battery pack or other accessory device attachable to a wireless telephone handset. The mobile unit is operated to assess some characteristic of each of the alternative transmission modes, and based on the assessment, a preferred mode is determined. Data is transmitted via the preferred mode. The unit may include a GPS locator, so that the transmitted data may include the location of the unit. A call center is connected via the Internet Protocol and/or through the Public Switch Telecommunication Network, and receives the data for processing, such as to return information to the user about the location.